1. Field of the Invention
The present invention relates to an image heating apparatus to be applied to an image forming apparatus such as a copying machine and a printer, and more particularly to an image heating apparatus provided with a movable (moving) body which slides on a guide member and moves together with a recording material.
2. Related Background Art
In a heating apparatus including: a film, which is a movable body; a guide member for guiding the film; a pressurizing member pressure contacting with the guide member via the film to form a nip; and heating means for raising the film in temperature to heat a member to be heated, which is conveyed within the nip with movement of the film, when the process speed is speeded up, that a frictional resistance between the film and the guide member becomes high, thereby there may result a drawback such as a deviation of the film and a generation of a wrinkle.
In Japanese Patent Application Laid-Open No.9-237001, it has been disclosed that on a guide surface of the guide member for guiding the film, there are provided a plurality of rib-shaped guide portions which are spaced apart in a moving direction of the film or in a direction for intersecting the moving direction of the film, whereby there is provided the effect that frictional resistance between the film and the guide member is reduced or the deviation of the film and occurrence of a wrinkle are restrained.
However, there has been a problem that when the guide member is provided with such a convex portion as the rib, the film is prone to be damaged.
Also, in a heating apparatus of a film heating system, lubricant (lubricating fats and oils or the like) has been conventionally interposed between the film and the guide member to thereby reduce the frictional resistance. In the case of an apparatus having the rib-shaped guide portions, however, it is difficult to uniformly disperse lubricant between the film and the guide member, and lubricant might leak out from an end portion of the film in the widthwise direction due to the use over a long term, thereby the effect of the lubricant being interposed is not exhibited sufficiently.
It is an object of the present invention to provide an image heating apparatus for improving slidability of the movable member on the guide member without causing any damage to the movable member.
It is another object of the present invention to provide an image heating apparatus including: a movable member; a guide member for guiding a movement of the movable member; and a back up member for forming a nip portion with the guide member via the movable member, in which a recording material bearing an image at the nip portion is pinched and conveyed, and the image on the recording material is heated by a heat from the movable member side, and the guide member has a recess portion in a guide portion different from the nip portion.
Still another object of the present invention will be apparent from the following description.